Method and means for controlling the flow of liquid



Nov. 3, 1936. 2,059,721

METHOD AND MEANS FOR CONTROLLING THE FLOW 0F LIQUID c. M: ASHLEY Filed Dec. 2. 1933 INVENTOR. Carlyle lnflshley Al -MM ail.)

A TTORNEY Patented Nov. 3, 1936 the condenser.

UNITED STATES PATENT OFFlCE METHOD AND MEANS FOR CONTROLLING THE FLOW OF LIQUID Carlyle M. Ashley. Maplewood, N.

mesne assignments to Corporation, Newark, N.

New York J., assignor, by Carrier Engineering J., a corporation of Application Decei nber 2, 1933, Serial No. 700,670 13 Claims. (Cl. 62-152) This invention. relates to a refrigeration system, and more particularly, to the disposal of liquid condensate from the condenser of such a system.

It is an object of this invention to remove a volume of condensate from a condenser maintained at sub-atmospheric pressure, to supply a portion of the condensate to an evaporainr maintained at an even lower pressure, and to discharge the remaining condensate at atmospheric pressure over, the surfaces of the cOndenser.

level to another, and

to augment this lifting effect by introducing vapor into the liquid to be lifted.

Still another object of the invention is to supply a liquid to an evaporator from a source located below the evaporator, and to prevent the siphoning of liquid from the evaporator when pressure at the source.

0 the pressure in the evaporator is .equal to the Another object of the invention is to withdraw a portion of condensate from the inside of a condenser, to discharge this condensate over the outer surfaces of the condenser, and to prevent a flow of water into the condenser whenever the condenser is inoperative.

A feature of the invention resides in the provision of an inverted liquid trap between an evaporator and a condenser located ,below the evaporator.

Still another feature of the inventionresides in the provision of means for admitting vapor to the condensate in the leg of the inverted trap which is subjected to condenser pressure.

Still another feature of the invention resides in the provision of a siphon breaker in theleg of the inverted trap which passes into the evaporator.

A further feature res ides in provision of a circuit for supplying liquid over the surfaces of a condenser,-an aspirator in said circuit for withdrawing liquid from the inside of the condenser,

and an inv'ertedtrap in the liquid circuit for preventing the flow of liquid from said'circuit into Other objects and f hereinafter. Fig. 1 is an elevation al view, partly in section,-

.high pressureleg 2! of of a refrigerating system, of the steam ejector type, suspended from the floor of a conventional railroad car;

Fig. 2 is a sectional elevational view of a portion of the apparatus of Fig. 1;

Fig. 3 is a fragmentary view of a float check valve which may be used in connection with the apparatus of Fig. 1. 1

With reference to the drawing, similar designations referring to similar parts, Fig. 1 shows a refrigeration apparatus of the steam ejector type to which this invention is" particularly applicable, though to which it is in no sense limited. The apparatus comprises an evaporator 5 in which is a body of water 6 in open communication with head i and entrance diffuser 8 ofa steam ejector generally designated by numeral 9. In operation, steam admitted through pipe 00, is expanded, by means of a suitable nozzle positioned within head i, to a desired low pressure. The high velocity jet of steam issuing from the nozzle entrains water vapor from evapprator 5, thereby lowering the pressure therein.

Consequently, water it boils, thus absorbing heat orator 5. Due to the difference in the pressures existing ln-evaporator 5 and condenser l6, condensate from well l9 flows upwardly through the trap 20 and discharges into evaporator 5 through low pressureleg 22. It is apparent that as the liquid rises in leg 2|, the pressure to which it is subjected falls. A hole 23 in the high pressure leg 2|,located within well l9, but above the normal liquid level, allows vapor from the well to pass into the liquid condensate in leg 2!. This, incombination with the boilin which must occur'due'to the falling pressure referred to above," results ini'an' ebullition of vapor throughout the liquid in leg 2|,

' which, in turn, causes'areductionin the amount of liquid contained in leg 2 I. Consequently,

densate over the hump in inverted trap 20, and into evaporator 5.

The pressure existing in condenser |6 varies with each change in outside weather conditions, whereas the pressure in evaporator 5 remains substantially constant. Therefore, leg 2| of trap 20 must be so designed that a minimum pressure difference, plus the vapor lift effect just described, will be suflicient to force the requisite quantity of liquid from well l9 into evaporator 5. However, when the pressure difierence is above this minimum, the flow of liquid from the well, if uncontrolled, would be in excess of that actually required, and would, therefore, tend to increase the liquid level in evaporator 5 above the desired point. To control the liquid flow, applicant pro-- vides a hollow ball 24 floated by liquid in well 25 of evaporator 5. As the liquid level in the evaporator rises responding to liquid flow from trap 20, the ball is floated against the open end of low pressure leg 22. Conversely, as the liquid level falls, ball 24 is floated away from the end of leg 22,' and a flow of liquid into the evaporator is again established. Preferably, ball 24 is made of rubber, because of its resiliency. Hence, when the ball is floated against the end of leg 22, the rubber surfaces give, thus compensating for any irregularities in the seat.

Whenever the ejector is inoperative, i. e., no steam is supplied to the nozzle through pipe ID, the pressures in evaporator 5 and condenser |B are equalized through diffusers 8 and i3. Fur-- ther, the water in the cooling circuit, including pipe spray pipes l2, and an air cooling coil (not shown) flows back into evaporator 5, thus materially raising the liquid level therein. If, then, when the system is inoperative, float ball 24 should fail to seat properly, it is apparent that trap 20 would constitute a perfect syphon, and consequently, liquid would flow from evaporator 5 into condenser l6. To prevent this possibility, applicant provides a hole 26 in low pressure leg 22 at a point above the maximum liquid level in evaporator 5. Thus, any possible syphon is effectively broken.

As can be seen in Fig. 1, head 1 of ejector 9, for purposes of space economy, is joined to an end of evaporator 5. If the level of water in the evaporator should rise, as under conditions described above, it is apparent that the water would flow through the ejector and thence into condenser l6. To prevent this, applicant provides a U- shaped trough 4 I extending from head I throughout the length of the evaporator 5. In this manner, open communication between the evaporator and ejector is maintained, but passage of water therethrough effectively prevented.

For the purpose of liquefying the compressed vapors in condenser l6, applicant utilizes the principles of evaporative cooling. To this end, water from sump 27, through pipe 28, pump 29, inverted trap 30, aspirator 3|, pipe 32,'and header 33 is sprayed over the surfaces of tubes I5. Air flowing in the direction indicated by the arrows, contacts the wet tube surfacesabsorbs a part of the water vapor, and consequently, tends to cool the condenser to a temperature corresponding to the wet bulb temperature of the incoming air. The moisture laden, heated air is discharged upwardly through louvres 34. I

Obviously, some of the water from sump 21 is constantly being lost through this evaporative process. To make up for this loss, at least partially, applicant withdraws 'from condenser l6 that quantity of water corresponding to the steam supplied through pipe l0 and discharges it over the condenser surfaces. To this end, condensate from well l9, through pipe 35, and float check valve 36, is supplied to aspirator 3|, and therein mixed with water from sump 21. The remaining water deficiency is supplied to sump 21 from an auxiliary make-up'water tank or other means (not shown).

As is well understood, the condenser and evaporator are both operated at pressures well below atmospheric, for example, at pressure ranging from 27-295 inches of vacuum. Therefore, when the system is inoperative, including pump 29, water from sump 21 would tend to flow through aspirator 3|, pipe 35, and well ill into the condenser. To prevent this, check valve 36 is provided in pipe 35. As can be seen from Fig. 3, water rising in pipe 35 will force ball 31 against seat 38, thus stopping any upward flow of liquid.

However, even the best check valves tend to leak. As an additional safety feature, applicant provides inverted trap 30, and a passageway 39, connecting the top of trap 30 with pipe 32. A swing check valve 40, of well known design, opens in the' direction indicated by the arrow 42. If check valve 35 leaks, water is drawn into the condenserboth from pipe 32 and from one leg of trap 30. A movement of liquid in trap 30 causes check valve 40 to open, thus providing a passageway to atmospheric pressure. Consequently, when all the water in pipe 32, one leg of trap 30, and passageway 39 is drawn into condenser |6, the vacuum is broken, the condenser fills with air, and any water contained therein drains from the condenser by gravity. This feature is of particular importance in preventing freezing of the condenser under certain conditions.

Aspirator 3| serves, in a well understood manner, the additional purpose of purging the system of air, and other non-condensable gases prior to, and during operation.

Since certain changes in carrying out the above process and in the constructions set forth, which 4 1. In a refrigeration apparatus, an evaporator,

a condenser, a steam ejector (connecting said evaporator and condenser, awell for collecting liquid from said condenser, an inverted trap connecting said well and said evaporator for supplying a portion of the liquid from said well to said evaporator, means for controlling the flow of liquid through said trap, and means for discharging the remaining portion of said liquid over the surfaces of said condenser.

2. In a refrigeration apparatus, an evaporator, a source of liquid located below said evaporator, an inverted trap connecting said evaporator and said source, and a syphon breaker in said trap for preventing flow of liquid from said evaporator to said source, said syphon breaker comprising an opening in the trap between. the extremities thereof.

3. In a refrigeration apparatus, an evaporator, a source for supplying liquid to said evaporator, an inverted trap connecting said evaporator and said source, means responsive to changes in the liquid level in said evaporator for controlling the flow of liquid from said source to said evaporator,

vacuum breaker for preventing a flow of liquid into said condenser from an outside source.

5. In a refrigeration apparatus, an evaporator, a condenser the lower portion of which is below said evaporator, an ejector connecting said evaporatorand the upper portion of said condenser, an inverted trap for supplying a portion of liquid from the lower part of said condenser to said evaporator, means for preventing a flow of liquid from said evaporator to said condenser, means for supplying the remaining portion of said liquid to the outer surfaces of said condenser, and means for preventing a flow of liquid into said condenser from an outside source.

6. In a refrigeration apparatus, a condenser, a liquid sump located below said condenser, a liquid circuit for conveying water from said sump to the outer surfaces of said condenser, an aspirator in said circuit for withdrawing air and a portion of liquid from said condenser, and means for preventing a flow of liquid from said circuit into said condenser.

7. In a refrigeration apparatus, a condenser, a liquid sump located below said condenser, a liquid circuit for conveying liquid from said sump to the outer surfaces of said condenser, an aspirator for introducing into said circuit liquid from the condenser, and a vacuum breaker in said circuit between said sump and said aspirator.

8. In a refrigeration apparatus, a condenser, a liquid sump located below said condenser, a header for spraying liquid over the surfaces of said condenser, a liquid circuit connecting said sump and said header, means for introducing into said circuit liquid from the condenser, an inverted trap in said circuit between said means and said sump and means for admitting air into the top of said trap for preventing a flow of liquid from said circuit to said condenser.

9. In a refrigeration system, an evaporator, a

condenser, a well for collecting condensate from the condenser, an inverted trap connecting said well and the evaporator, means for controlling the flow of liquid through the trap to the evaporator, and means for drawing liquid from the well for use in cooling the condenser.

10. In a refrigeration system of the character described, an evaporator, a condenser, a well for collecting condensate from the condenser, an inverted trap connecting the well to the evaporator. a float ball for controlling the flow of liquid through the trap, the ball being arranged to stopthe flow of liquid through the trap by pressing within the pipe opening constituting the evaporator end of the trap when the liquid in the evaporator rises above a prescribed level, the

ball dropping from its abutting position when the liquid in the evaporator falls below the prescribed level.

11. In a refrigeration system, an evaporator, a

condenser, a receptacle for collecting condensate from the condenser, a trap connecting the receptacle and the evaporator, and means comprisinga conduit having an open end submerged in liquid within the receptacle and an opening in the conduit above the level of liquid in the receptacle, the conduit constituting one leg of the trap, said opening permitting the introduction of vapor within said leg whereby a mixture of vapor and liquid will be formed in the leg.

12. In a system of the character described, an evaporator, acondenser, a collecting chamber for receiving condensate from the condenser, means for supplying liquid from said chamber to the evaporator, the pressure in the evaporator being less than atmospheric and means for supplying liquid from the chamber to the outer surface of the condenser under atmospheric pressure. 

